Imaging apparatus

ABSTRACT

Apparatus having more than one separate object to project along partially separate optical paths having the same image plane for simultaneous superposition of the images of the two objects. The objects are transparencies with one containing the information to be imaged and the other premade to be the border for it. Both objects move in a carriage relative to an exposure slit for simultaneous scanning projection onto a moving member at the image plane.

United States Patent n91 Wharton et a1.

IMAGING APPARATUS [75] Inventors: Armistead Wharton, Henrietta; Earl V. Jackson, Penfield, both of NY.

[73] Assignee: Xerox Corporation, Rochester, NY.

22 Filed: Nov. 14, 1969 21 Appl. No; 876,847

52 u.s. Cl. ..355/46, 355/3, 355750 [51] Int. Cl. ..G03b 27/46 [58] Field of Search ..355/3, 17, 46, 5O

[56] References Cited I UNITED STATES PATENTS 1,666,304 4/ 192 8 Proctor ..353/48 1,857,135 5/1932 Brenkert .353/34 1,919,922 7/1933 Baker ..353/34 2,301,274 11/1942 Greiser.... 353/30 X 3,238,841 3/1966 Bjelland.... .....352/81 X 3,280,697 10/1966 Henley ..355/52 X 51 Apr. 17, 1973 Primary Examiner-John M. Horan Attorney-James J. Ralabate, David C. Petre and Barry Jay Kesselman [5 7] ABSTRACT Apparatus having more than one separate object to project along partially separate optical paths having the same image plane for simultaneous superposition of the images of the two objects. The objects are transparencies with one containing the information to be imaged and the other premade to be the border for it. Both objects move in a carriage relative to an expo-.

sure slit for simultaneous scanning projection onto a moving member at the image plane.

1 Claim, 12 Drawing Figures PAIENIEB R 3.728.018

SHEET 1 UF 7 INVENTORS ARMISTEAD WHARTON EARL V. JACKSON ATTORNEY PATENTEU APR 1 7191s SHEET 2 OF 7 PATENTEB APR 1 71m SHEET 3 or 7 mmmwmw 73 PATENTEDAPRI 1 m1 3,728,018

SHEET 4 UF 7 FIG. 5

'rllllllll SOL-l 1 IMAGING APPARATUS This invention relates in general to projection systems and more particularly to imaging multiple inputs simultaneously into a common image.

Other inventions have been disclosed to superimpose various object inputs onto an image plane to form a single copy. Among them is an invention disclosed in US. Pat. No. 3,439,983 issued on Apr. 22, 1969 to J. H. Blow, Jr. The apparatus for producing copy from simultaneous inputs shown there includes projected and reflected data projects operating along a common, single optical path to form a composite image at a single image plane. The apparatus functions differently from the instant invention for reasons disclosed herein.

One purpose of the invention includes forming integrated composite images, mixing information along the entire format of the final copy formed at the image plane and transferred to a single copy sheet. Another important use is for format layout. This latter use for the invention has been recently increased because of the discovery of the new imaging system for forming black and white or full color images through the use of photoelectrophoresis. The inventions described in U.S. Pat. Nos. 3,384,565; 3,384,566 and 3,383,993 include a system where photoelectrophoretic particles migrate in image configuration providing a visual image at one or both of two electrodes between which the particles are placed in suspension. The particles are photosensitive and apparently undergo a net change in charge polarity or a polarity alteration by interaction with one of the electrodes upon exposure to activating electromagnetic radiation. Mixtures of 'two or more differently colored particles can secure various' colors of images. The particles in these mixes may have overlapping or separate spectral response curves and are usable in subtractive color synthesis. The system is extremely effective in reproducing continuous tone images such as photographs. The particles within the suspension will migrate from one of the electrodes under the influence of an electric field when struck with energy of a wavelength within the spectral response of the colored particles. After an image is formed it is generally transferred to a sheet of material such as white' paper. The system can be used in true color reproduction on a direct positive base. Therefore, the portions of the imaging suspension struck by light lose all particles except those reproducing optically the same color as the light striking them. This is because the system operates on a subtractive color basis. That portion of the image which is to be white will be void of particles and those portions that are to be black will contain three particles of a cyan, magenta, and yellow coloring giving a black visual appearance.

When projecting an image for obtaining a full color copy by the above process on a transfer sheet it is aesthetically desirable to have a white border around the image. lf the image is smaller than the imaging capacity of the member on which the image is formed or the sheet to which the image is transferred, there will be a black border of particles surrounding the image on the final copy sheet.

It is an object of this invention to overcome the above noted difficulties.

Another object of this invention is to improve simultaneous projection techniques. A further object of this invention is to improve image formats.

Yet another object of this invention is to improve simultaneous scanning techniques. Still a further object of this invention is to improve efficiency of multiple projection systems. Yet another object of this invention is to improve the accuracy of multiple scanning systems producing a single image while anotherobject is to improve copy format in photoelectrophoretic imaging systems.

These and other objects of this invention are accomplished by use of means to simultaneously project a plurality of objects along predetermined, at least partially separate, optical paths including a single image plane and incorporating means to scan the objects at a synchronous speed with a member moving through the image plane so that a flowing image of the multiple objects is simultaneously placed on the moving member at the image plane. The invention is illustrated and described in a preferred environment operating in conjunction with other apparatus to automatically produce copies of the objects held within the film frames of the invention. Nevertheless, the invention need not be confined to such an environment and should be broadly construed within the limitation of the claims. It may be that other processes or apparatus are or will be invented having optical needs that can be satisfied by the apparatus described and claimed herein. And it is the intention of this patent application to describe and claim an invention for use in many projection apparatus.

Objects and advantages of this invention will become apparent to those skilled in the art after reading the following description taken in conjunction with accompanying drawings wherein:

FIG. 1 schematically illustrates an embodiment machine for forming photoelectrophoretic images;

FIG. 2 is a front view of the projector asviewed from the schematic illustration of FIG. 1;

FIG. 3 is a left side view of the apparatus of FIG. 2;

FIG. 4 is a bottom view of the apparatus;

F l6. 5 schematically illustrates the scanning drive system of FIGS. 1-4;

FIG. 6 illustrates an object carriage withan object therein;

-FIGS. 7 and 8 illustrate slit scanning members, an

FIGS. 9-12 are schematic illustrations of alternate optical embodiments of the invention.

ofa

Referring now to the figures, FIG. 1 shows a machine I during imaging. The term photosensitive" for the purposes discussed herein refers to the property of a particle, which once attracted to an injecting electrode, will alter its polarity and migrate away from the electrode under the influence of an applied electric field when exposed to activating electromagnetic radiation. The term suspension is defined as a system having solid particles dispersed in a solid, liquid or gas; nevertheless, the suspension preferentially used in the embodiment described herein is of the general type having one or more types of solid particles suspended in a liquid carrier. The term imaging electrode will also be used herein to describe that electrode which interfaces with the injecting electrode through the suspension and which once contacted by activating photosensitive particles will not inject sufficient charge into them to cause them to migrate from the imaging electrode surface. It has a dielectric surface with a resistivity of ohm-cm or greater and has a conductive inner core. The imaging zone or imaging area" is that zone between two electrodes where photoelectrophoretic imaging occurs.

The particles used in the suspension are generally insulating when not struck by activating radiation within their spectral response curve. When they are struck with such radiation under the influence of an electric field and in close position to the injecting electrode, they migrate to the imaging electrode which is held at an opposite potential relative to the injecting electrode.

Briefly, the photoelectrophoretic imaging process may be thought to occur when these steps take place: l) migration of the particles toward the injecting electrode due to the influenceof a field placed between electrodes, (2) the generation of charge carriers within the particles when struck with activating radiation, (3) particle deposition on or near the injecting electrode surface, (4) phenomena associated with the forming of an electrical junction between the particles and the injecting electrode, (5) particle charge exchange with the injecting electrode, (6) electrophoretic migration toward the imaging electrode, and (7) particle deposition on the imaging electrode. This leaves a positive image on the injecting electrode.

If all of the particles in the system are sensitive to one wavelength of light or another and the system is exposed to an image with that wavelength of light, a positive image will be formed on the surface of the injecting electrode by the subtraction of bound particles from its surface leaving behind particles in the unexposed areas only. The imaging suspensions may contain one, two or three or more different particles of various colors having various ranges of spectral response. In a monochromatic system the particles included in the suspension may be of any color and produce any color and the particle spectral response is relatively immaterial as long as there is a response in some region of the spectrum which can be matched by a convenient radiation expo sure source. In polychromatic systems the particles may be selected so the particles of various colors respond to difference wavelengths in the visual spectrum thus allowing for color separation. By using cyan, magenta and yellow particles, standard optical color subtraction can be used to form a direct positive color image on the object projected.

The injecting electrode 1 forms a portion of a cylinder held in a housing 2 and is journaled for rotation in the direction indicated by the arrow about a shaft 3. The injecting electrode 1 is transparent and is made up of a layer of optically transparent glass 4 overcoated with a thin optically transparent layer 5 of tin oxide or other electrically conductive material. A particular material suitable for this electrode is available under the name of NESA glass manufactured by Pittsburgh Plate Glass Co., Pittsburgh, Pa. Theinjecting electrode 1 is formed as a portion of a cylinder housed within the metal housing 2.

The machine shown schematically is positioned where the injecting electrode cylinder portion is about to be rotated in a predetermined path to a cleaning station labeled A where a plurality of cleaning members such as belts 6, 7 and 8 contact the conductive surface 5 of the injecting electrode.

The next station in the path of movement of the injecting electrode is the inking and imaging Station B. Here, on the first pass of the injecting electrode 1 through Station B the first imaging electrode 16 interfaces with the conductive surface 5 of the injecting electrode 1.

The optical system at Station C projects simultaneously, objects to form an image at the imaging zone of the electrodes 1 and 16 at Station B. This imaging zone is the image plane of the projection system of Station C.

The imaging electrode roller 16 moves in rolling interface relation with the conductive surface 5 of the injecting electrode 1 and functions both to supply suspension to the injecting electrode and to image that suspension between the injecting electrode surface 5 and the surface of the electrode 16. I

The injecting electrode continues to rotate at a constant speed through a complete rotation ofthe predetermined path. It travels without contacting any elements located around the periphery of the path until it again reaches the Station B at the imaging zone. Now, however, the injecting electrode 16 has been moved out of its interfacing position and a second imaging electrode 29 is moved to thatposition to operate with the injecting electrode 1. This is accomplished by moving the carriage 28 after lowering the tank 26 housing the first imaging electrode 16 and then raising the. tank 30 housing the second imaging electrode 29. The second imaging electrode 29 moves in rolling interface relation with the injecting electrode surface 5 as that surface passes through the imaging Station B for the second time.

At this time the objects in the optical system at Station C are scanning in the projector 34 such that the scan is synchronized with the movement of the injecting electrode and with the original scan to project a flowing image moving at the same rate and in the same relationship as during the first scan. This produces a reinforced double image at the surface 5 of the injecting electrode 1 at the imaging zone.

The injecting electrode then passes into the transfer Station D. The transfer roller 40 carries a sheet of support material between it and the surface 5 of the injecting electrode 1. Before the sheet contacts the surface 5 of the injecting electrode it is moistened with liquid that will aid in transferring the particles of the suspension on the surface 5. Virtually all of the particles remaining on the injecting electrode 1 are transferred to the transfer sheet which is then released from the transfer roll and transported via vacuum transport 41 out of the machine environment. A vacuum refers to a pressure that is less than atmospheric though not necessarily zero.

FIGS. 2-4 show mechanical drawings of a transparency projector for use in conjunction with the machine of FIG. 1. The projector 34 (FIG. 1) operates along two optical paths 43 between the objects and the imaging zone of the surface 5 of the injecting electrode and the imaging electrodes. The illumination is provided by lamps held in a lamp cooling housing 45. Cool air is blown over the lamps through the cooling duct plenum 46 by a fan (not shown) and a connecting hose 62. The film transparencies are mounted in the mounting carriage transport 47 and are protected from excessive heat from the lamp 44 by a heat absorber placed between the lamps and the condenser lens assembly 49. The entire assembly is mounted within the housing 50 on vertical frame plates such as the plate 51. A shutter assembly 52 blocks out the light from the lamps 44 when the transparencies are not being projected such as on the return scan stroke.

The'film transport 47 is mounted on a transport slide rod over which the transport assembly 47 moves in relation to the slide bearing block 54. The motion is timed in synchronism with the movement of the injecting electrode 1. Lenses are mounted within each of the lens assemblies 55 and 56. The lenses remain stationary on a mounting block 63 during the scan motion while only the film transport with two frames of film therein move. One of the two frames of film contains the transparency object to be imaged having the information thereon of importance for copying. The other film frame has a transparent border with an opaque center.

The combination of the two simultaneous projections forms a final copy having the information from the object film frame surrounded by a white border from the projection of the transparent border film frame. Since the transparent border film frame provides the full spectral light from one lamp 44 for striking the imaging zone at the image plane, all of the particles at those portions of the imaging zone struck by the light migrate away from the injecting electrode 1 leaving none to be transferred to the support sheet (generally white) at the transfer Station D. A return spring 57 is mounted between the film transport 47 and the immovable bearing block 54 to ensure proper return of the transport and the film therein after the scan for imaging.

The scan is directed from the drive system maintained on the injecting electrode drum to ensure proper synchronism with the movement of the injecting electrode. The drive scan system moves a crank arm 58 coupled to a crank shaft 59 and a transport crank arm 60. The crank shaft 59 passes through the vertical object housing 47 mounted to it to move through the stationary block. The cable movement causes the scanning objects to present a flowing image at the imaging zone between the injecting electrode surface 5 and the imaging electrode 16 or 29. The image is moving at the same speed as the surface velocity of the two interfacing electrodes. A bias spring 78 ispinned to the dog arm 68 and the cable pulley 71 the latter at the pin 79. This biases the dog arm into contact with the rise 67 on the cam 66.

On the scan stroke end the solenoid SOL-1 is de-activated to strike the dog arm for disengaging it from the rise 67 on the cam 66. The greatest force now exerted on the scanning system is from the return spring 80 pinned between the frame of the machine and the crank arm 58. This forces the crank arm 58 about the shaft 59 moving the pulley 76 and the cable 72 wrapped thereabout. This moves the cable pulley 71 in the reverse direction from its scanning movement. It comes to rest when a dog 81 intimately fastened to its surface strikes an adjustable return stop 82.

The apertures 86 and 87 for the two object frames hold the object film and border film in the carriage 47. The two film frames can be placed interchangeably in either of the apertures since both lens systems including the lenses 88 and 89 are aligned to project to the exact same area at the image plane at the contact zone.

frame plate 51 at a bearing 65. A follower 61 is at- I tached to the crank arm for pushing against the transport 47 moving it along with the transport slide rod 53. The return spring57 forces the carriage 47 against the follower 61. This takes up any slack in the drive cable 72.

The scanning of the objects is synchronized with the movement of the injecting electrode 1. Therefore, the entire scan system is driven by the rotating shaft 3 of the injecting electrode drum 1. The shaft 3 rotates in the direction shown in FIG. 5 moving therewith a cam 66 having an acute rise 67 on its profile. The rise 67 engages the dog arm 68 at a dog 69. The dog arm is pinned by pin 70 to a pulley 71 that engages the cable 72 atthe cable anchor 73. The cable travels over idler pulleys 74 and 75 and connected to the machine frame after passing over the driven pulley 76. When the dog arm 68 is driven by the cam 66, it pulls the cable 72 which in turn rotates the crank arm 58, the shaft 59 and the crank arm 60. The follower 61 pushes againstthe drive block 77 which is intimately connected to carriage 47. The drive system causes the rail 53 and the The optical conjugate is adjustable by moving the assembly vertically along the vertical frames 51. Adjusting slots within the frames such as slot are provided with alignment pins 91 and loosenable adjusting clamps 92. The pins 91 ensure proper horizontal alignment while the loosening of the adjusting means 92 and the movement of the projecting assembly relative to the machine and to the vertical frames takes place. After proper adjustment, the adjusting clamps 92 are tightened against the frame plate 51 locking the transparency projection system in its new position.

The object transport is driven by a cable 72 running on a pulley 76 which in turn attaches to the crank arm 58. The motion given to the film transport 47 ispreset on the drive shaft on the injecting electrode drum assembly. Since the driving mechanism is physically tied in with the movement of the injecting electrode continuous synchronous movement is assured between the scanning transport 47 and the injecting electrode 1.

FIG. 6 shows a layout of two partially transparent objects in a carriage for use in the equipment described herein. They are shown in a common carriage 101 having two apertures for supporting the two object frames. The first object 102 can be slipped into the transport and has an opaque jacket 103 made out of cardboard, plastic or other materials such as are frequently used for mounting 35 mm transparency slides. The information portion to be projected is contained in the object section 104 of the transparency. The second object frame has a clear transparent outer border 105 with an opaque blocked out center portion 105a. This border frame format can be permanently affixed to the carriage 101 or removably positionable therein as can be the information transparency slide 102. The transport with the objects therein is adapted to be moved for scanning projection in any direction although for convenience the scan would ,be either in the direction indicated by the arrows 106 or by the arrows 107.

If the motion were in the direction indicated by the arrows 106 a scanning slit member 108 (FIG. 7) would be used in conjunction with the film transport. This member has slits 109 and 110 out through it to permit the light from the objects to pass to the image plane.

The slits are parallel along their major direction which would be 90 to the direction of scan.

If the scan were to be in the direction indicated by the arrows 107 then the scan slit member would look like the arrangement of FIG. 8. Here, the member 111 has the two slits 112 and 113 allowing light to pass therethrough in a single line. A member such as this is usable in the apparatus as shown in FIG. 3. It should be noted that the slits may be located anywhere relative to one another so long as they are functional with the placement of the object frames in the object holding carriage and with the direction of scan for projection to a moving image receptor at the image plane.

FIGS. 9-12 show various optical arrangements of the optical system employed in this invention. The first arrangement employs the insertion of a partially silvered mirror or beam splitter 114 into the optical path of a transparency projection system. An information transparency is projected through the beam splitter 114 while a second transparency 116, for generating a white border, is injected into the system by reflection from the beam splitter. This approach necessitates two carriages 117 and 118 shown as moving at 90 to each other with two lamp sources 119 and 120 and condenser systems 121 and 122. The slits 123 and 124 are maintained in two separate slit plates 125 and 126 respectively for enabling the passage of light to the projection lens 127. The two transports 117 and 118 are simultaneously moved between the lamp systems and slits to project both objects through the projection lens 127 and along the optical path 128 to the image plane. The optical beam 129 coming from the lamp 120 and the film 116 is reflected by the beam splitter 114 through the lens 127 while the beam 115 from the information transparency and the lamp 1 19 is simultaneously passed through the beam splitter so that both comprise the light rays of the beam 128 coincident in the optical path to the image plane.

FIG. is an alternative embodiment to simultaneously project a plurality of images using a transport layout similar to FIG. 6 and moved in the scan direction 106. Both of the objects are mounted in a single transport carriage 130 and move in unison past the scanning slits of the slit member of FIG. 7. There is no beam splitter in this system and the two separate optical paths are combined through a pair of prisms 131 and 132, which are replaceable by an equivalent mirror system. The light source is supplied by two lamps 133 and 134 having each a condenser system 135 and 136 respectively. The light path moves through the object carriage 130 which'scans in the direction indicated by the arrow so that both objects are simultaneously presented via the prisms 130 and 132 to the projection lens 137 to be combined into a single optical path from the lens to the image plane.

FIG. 1 1 shows a different embodiment incorporating one lamp 140 having two condenser systems 141 and 142 to illuminate the objects 143 and 144 maintained in a single object carriage transpor 145. The light from the lamp 140 passes through the transparent areas of the objects to the lenses and 151 when the film carriage openings reach the slits 146 and 147 of the slit member 148 during the scanning movement of the slide carriage 145. In order to illuminate the object 144 a mirror 149 is inserted to reflect light from the lamp 140 into a path crossing the object 144. The light passing through the slits 146 and 147 is imaged through the projection lenses 150 and 151 respectively. These send individual light beams to a common image plane where they combine to form a single simultaneous composite image on a moving member passing through the image plane. I

FIG. 12 utilizes a single illumination source, lamp and a single condenser system 161 to project light through both apertures 162 and 163 in the object carrier transport 164. The objects 165 and 166 are centered relative to the apertures and to the two projection lenses 167 and 168. The scanning occurs by traversing the objects with the slit plane 169 and the scanning slits 170 and 171 therein. The slits are spaced to begin and end the scanning operation allowing the passage of light and cutting off the passage of light at the same time for both objects.

The optical paths 172 and 173 of each of the objects are separate until they impinge upon the image plane where they coincide for simultaneous projection of the information object and the border on the center masked object.

While this invention has been described with reference to the structures disclosed herein and while certain theories have been expressed to explain the experimentally obtainable results obtained, it is not confined to the details set forth; and this application is intended to cover such modifications or changes as may come within the purposes of theimprovements or the scope of the following claims.

What is claimed is:

1. Optical projection apparatus including:

a document conveyor assembly adapted to support two transparent documents having different indicia thereon representative, when viewed together, of a composite image, said document conveyor assembly positioned for movement through an object plane, in a first direction, said document conveyor assembly adapted to support the transparent documents disposed one from another along said first direction,

a light receiving member positioned at an imaging plane adapted to concurrently receive light images of the transparent documents supported on said document conveyor assembly,

two lens means fixedly positioned between said document conveyor assembly and said light receiving member, said lens means being displaced one from another along said first direction,

means to move said light receiving member through said imaging plane in a second direction, opposite from said first direction,

means to move said document conveyor assembly and, consequently, transparent documents supported thereon through said imaging plane in said first direction whereby each lens is adapted to simultaneously project light images from a single transparent document supported by said document conveyor assembly,

to said first and second mentioned directions of motion, each slot being adapted to restrict the amount of light projected to said image plane from each transparent document, and

programming means to actuate said means to move said document conveyor assembly and said means to move said light receiving member in a correlated fashion whereby flowing images of transparent documents supported on said document conveyor assembly are concurrently projected to said light responsive member so that a unitive composite image may be created thereat.

l i i i 

1. Optical projection apparatus including: a document conveyor assembly adapted to support two transparent documents having different indicia thereon representative, when viewed together, of a composite image, said document conveyor assembly positioned for movement through an object plane, in a first direction, said document conveyor assembly adapted to support the transparent documents disposed one from another along said first direction, a light receiving member positioned at an imaging plane adapted to concurrently receive light images of the transparent documents supported on said document conveyor assembly, two lens means fixedly positioned between said document conveyor assembly and said light receiving member, said lens means being displaced one from another along said first direction, means to move said light receiving member through said imaging plane in a second direction, opposite from said first direction, means to move said document conveyor assembly and, consequently, transparent documents supported thereon through said imaging plane in said first direction whereby each lens is adapted to simultaneously project light images from a single transparent document supported by said document conveyor assembly, illumination means positioned on the side of said document conveyor assembly opposite from said lens means, said illumination means adapted to create light for permitting projecting of light rays from transparent documents supported by said document conveyor assembly to said imaging plane, light condensor means positioned between said illumination means and said document conveyor assembly and being adapted to concentrate the light created by said illumination means, light baffle means, fixedly positioned between said document conveyor assembly and said lens means, said baffle means having a pair of slots transverse to said first and second mentioned directions of motion, each slot being adapted to restrict the amount of light projected to said image plane from each transparent document, and programming means to actuate said means to move said document conveyor assembly and said means to move said light receiving member in a correlated fashion whereby flowing images of transparent documents supported on said document conveyor assembly are concurrently projected to said light responsive member so that a unitive composite image may be created thereat. 